Thread: Is long lived nuclear waste worse than short lived waste?

As a lay person interested in nuclear physics and nuclear reactors, I have a read a lot of articles concerning the safety of nuclear reactors. Two things often singled out as the most dangerous aspects of commercial nuclear reactor technology seem to be
1/. very long lived nuclear waste (the actinides), and
2/. (unintentional) dispersal of radioactive discharge over a large area, say from a nuclear accident like Chernobyl.

The assumption seems to be that short lived waste is inherently better than long lived waste, and that radioactive discharge over a small area is always inherently superior to discharge over a large area. No other qualifications seem to be made in regard to these two assumptions.

Yet it seems to me that long lived waste by definition must be less intensely radioactive than short lived waste, since the half life is a measure of the rate at which the atoms decay, and also that the larger the area over which a particular quantity of radioactive material is dispersed, the thinner it will be spread and the less radiation there will be per unit area.

In many respects then it would seem that if you do have a nuclear accident that releases a significant quantity of radioactive material, then it would be best if it were long lived rather than short lived and dispersed over a large area than a small one - the exact opposite of conventional wisdom.

For example, suppose all the radioactive material from Chernobyl had been evenly dispersed over the entire planet - would there have been any noticeable effect besides a small increase in the background radiation levels? (I do not know how much radiation was released versus the amount of normal background radiation - so this is an ill informed guess. Perhaps someone will advise if this is correct?).

Please note that I have not included any specifics concerning type of radiation nor amount of radiation, but then I am trying to "refute" these basic assumptions (long lived is worse than short lived, etc) which also have no specific details given. I know the real situation is much more subtle and complex than I have indicated - I am just trying to make a basic point about these assumptions.
:-D

Originally Posted by magneticrabbit

...- I am just trying to make a basic point about these assumptions.
:-D

to whom ?

Originally Posted by DrRocket

Originally Posted by magneticrabbit

...- I am just trying to make a basic point about these assumptions.
:-D

to whom ?

To anyone who reads the post?

The most generally accepted model for health effects of human radiation exposure is called the linear no-threshold model by which it is assumed that the health effects can be extrapolated linearly from events such as the bombing of Hiroshima and Nagasaki. By this model there would be no advantage to allowing a small dose to a large number of people, or a larger dose to a smaller number. The resulting deaths would be the same.

Some people think there is a threshold, or even a beneficial effect, called radiation hormesis, at low doses.
http://en.wikipedia.org/wiki/Radiation_hormesis

The obvious problem with contamination of a site with long lived isotopes is that it stays contaminated for a very long time. Whereas if it is short half-life isotopes, you would just have to keep people away until it decays off.

Originally Posted by Harold14370

The most generally accepted model for health effects of human radiation exposure is called the linear no-threshold model by which it is assumed that the health effects can be extrapolated linearly from events such as the bombing of Hiroshima and Nagasaki. By this model there would be no advantage to allowing a small dose to a large number of people, or a larger dose to a smaller number. The resulting deaths would be the same.

Some people think there is a threshold, or even a beneficial effect, called radiation hormesis, at low doses.
http://en.wikipedia.org/wiki/Radiation_hormesis

The obvious problem with contamination of a site with long lived isotopes is that it stays contaminated for a very long time. Whereas if it is short half-life isotopes, you would just have to keep people away until it decays off.

I am really only talking about cases where the radioactive material can be spread over a large enough area that the level of radioactivity is much lower than the background, and so where people can remain living in the area of release. If the radiation level is high enough that people cannot live in the area, then obviously the short lived stuff is much better than the long lived stuff.

I guess the point I am trying to make re nuclear "emissions" is analagous to the emissions from burning fossil fuels. An internal combustion engine in a typical car emits some gases, such as carbon monoxide, that in a concentrated form could easily kill a human being (such as might happen if the car was running in a closed garage), but these emissions are diffused into the atmosphere where everyone on the planet ends up inhaling them, but a such low levels that they do no significant damage.

The Universe as a whole including the Earth is filled with a diffuse level of radiation (solar wind, cosmic rays, natural decaying radioisotopes, etc). It seems this is unavoidable. It would appear there is nowhere in the Universe we know of where one could live in a radiation-free environment. Indeed as you point out regarding radiation hormesis, it may be possible that a completely radiation free environment would actually be undesirable, or at least of no significant benefit.

[quote="magneticrabbit"]

Originally Posted by Harold14370

. By this model there would be no advantage to allowing a small dose to a large number of people, or a larger dose to a smaller number. The resulting deaths would be the same.

That depends entirely on who gets to pick the small number that gets the large dose.

[quote="DrRocket"]

Originally Posted by magneticrabbit

Originally Posted by Harold14370

. By this model there would be no advantage to allowing a small dose to a large number of people, or a larger dose to a smaller number. The resulting deaths would be the same.

That depends entirely on who gets to pick the small number that gets the large dose.

yes, but in the grand scheme of the population, notwithstanding the idiocy of many people, the population would be affected the same regardless

[quote="Arcane_Mathematician"]

Originally Posted by DrRocket

Originally Posted by magneticrabbit

Originally Posted by Harold14370

. By this model there would be no advantage to allowing a small dose to a large number of people, or a larger dose to a smaller number. The resulting deaths would be the same.

That depends entirely on who gets to pick the small number that gets the large dose.

yes, but in the grand scheme of the population, notwithstanding the idiocy of many people, the population would be affected the same regardless

Not at all.

All men are created equal only wth respect to constitutional rights. The effect on the population on the other hand is strongly dependent on which individuals are eliminated.

Darwinian theory should tell you that. If the model indicates differently then it is the model that is flawed.

[quote="DrRocket"]

Originally Posted by magneticrabbit

Originally Posted by Harold14370

. By this model there would be no advantage to allowing a small dose to a large number of people, or a larger dose to a smaller number. The resulting deaths would be the same.

That depends entirely on who gets to pick the small number that gets the large dose.

There is of course no choice with most of the non-nuclear pollution. It is considered by most people acceptable to simply spew it out of a tall chimney, an exhaust pipe, or pump it into a convenient river or hole in the ground, and let it diffuse quietly into the eco-system. Out of sight, out of mind.

Originally Posted by magneticrabbit

There is of course no choice with most of the non-nuclear pollution. It is considered by most people acceptable to simply spew it out of a tall chimney, an exhaust pipe, or pump it into a convenient river or hole in the ground, and let it diffuse quietly into the eco-system. Out of sight, out of mind.

Even the non-nuclear pollution is nuclear sometimes.

Coal Ash Is More Radioactive than Nuclear Waste

Originally Posted by Harold14370

Originally Posted by magneticrabbit

There is of course no choice with most of the non-nuclear pollution. It is considered by most people acceptable to simply spew it out of a tall chimney, an exhaust pipe, or pump it into a convenient river or hole in the ground, and let it diffuse quietly into the eco-system. Out of sight, out of mind.

Even the non-nuclear pollution is nuclear sometimes.

Coal Ash Is More Radioactive than Nuclear Waste

Yes. Ive heard that coal fired plants produce lots of radioactive ash. Shame that these details are seldom reported in the news (being too complex and cerebral for the average punter) and hence a very biased and emotionally charged atmosphere pervades the nuclear arena - and the truth hardly gets a look in.